Dirt Bike Tire Pressure: A quick reference guide

When I first got my dirt bike, I had no idea what I should inflate the tires to.  I searched all over the internet and everyone had a different answer.

This post is my simple guide to setting the correct tire pressure on your dirt bike.

Generally, the tire pressure on a dirt bike should be between 6 and 18 psi with a traditional tire.  The most common tire pressure that avid dirt bike riders recommend is 12psi.  If you’re an average rider on an average bike riding on average terrain, set your tire pressure to 12psi and forget about the rest of this article.  However, if you want to customize your tire pressure perfectly to suit you and your riding style, then read on the for the full story.

There are a lot of caveats to the general rule of 12psi, and it’s a not the right setting for all situations, so please do take the time to read about some of the nuances to that guidance below.

Benefits and Drawbacks of Changed Tire Pressure

It may seem obsessive to change the tire pressure one psi up or down and expect much of a change, but even small changes in tire pressure make a difference.  If you think about it, 2 psi difference is a 20% change in the tire pressure.

Benefits of Higher Tire Pressure:

  • Higher speeds (if all else is equal)
  • Protects the tire and rim from impacts on rocks or other solid objects.  If you ride in Moab or other areas where you’ll be hitting lots of tree roots and hard sharp rocks during an off-road ride, then go up to 15psi.
  • Great for heavier riders who need more cushion

Benefits of Lower Tire Pressure:

  • Better traction
  • Great for official MX tracks where you know you’re not going to suddenly slam into a boulder or a tree root like when riding off road.
  • Great for lighter weight riders who press down less on the tires
  • Great on loose terrains like soft clay, mud, or loose rock.  If you’re riding mostly on sand, I’d drop down to 9psi.

Factors that Affect Tire Pressure

  • Type of tire used (Tubliss will use very different pressure than a typical tire)
  • Rider’s weight
  • Terrain (Rocky or hard surfaces require a higher pressure than loose mud)
  • Rider’s preference for protection of the tire (If you want great traction on most terrain, choose a low tire pressure, but be aware it can easily ruin your rims)

Get a Good Quality Tire Pressure Gauge and Pump

If you use the cheapo tire pressure gauge that you use on your car tires, you’re very unlikely to get a good reading.  Tire pressures in cars go much higher than on a dirt bike, so the gauge shows a more coarse scale.  You can’t tell the difference between 10 and 11 psi on most gauges.

I highly recommend you just get the PressCheck Air tire Pressure Gauge on Amazon.com.  It’s really cheap and it’s meant for dirt bike tires so it clearly shows your psi down to the half pound.  

For pumping your tires, you can use something as simple as a little bike tire pump.  It’ll work just fine.  However, that ceases to work well at the high psi’s needed if you ever move to a Tubliss system, or you just want something nicer so you can see the psi as you’re inflating.

The tire pump (compressor) I got is the one from Slime (same company as the green goop in bike tires).  Their compressor says it can go up to 150psi.  Now TONS of compressors claim they can do that, and none of them can that I’ve tried.  However, the Slime goes plenty high enough for a dirt bike tire.  It can realistically inflate to 105 psi.  You can get it on Amazon.com.

Setting the Front and Rear Tire Pressure Differently

Some riders like to set the tire of the rear and front tires at different psi levels.

For example, when riding very fast and hard in a motocross race, the rear tire will heat up.  The heat also increases the pressure in the tire.  So some riders will set the rear wheel at a lower psi than the front tire to compensate for how the tire will behave during the race once its warm.

Preventing Punctures

Tire pressure has a lot to do with the number of punctures you get in your tires.  Generally, a higher tire pressure will help to prevent flats.  This is because the tire compresses less when it hits hard objects and thus they are more likely to bounce off.

However, too high of a tire pressure can have issues of its own.

Tubliss is another option for preventing punctures.  This system has a small insert tube inside the rim that is set to an extremely high psi to prevent damage to the rims and lock the tire to the rim.  Then there is a larger outer area where there is no tube at all, and thus no possibility for pinch flats.  This area can be set to a very low psi for better traction.  Punctures are still possible, but there is a cool system for quickly filling them.

Another option for preventing punctures is a mousse.  They are cheap and they make it impossible to get any type of flat.  However, they are very heavy, and they only last 6 months.

What to Watch For

If the tire pressure is too low when you’re riding, you may notice a few things that will tell you that you should increase your tire pressure for the style of riding you do.  For example, if you feel the bike does not tightly corner, or you feel a loose wobble in the tire at medium speeds, then you’d know you’re too low.  The reduced cornering ability is due to the tire roll.  Another dead giveaway would be if you see your rims starting to get bent or dinged up, but before that happens you will likely feel it when out riding and your rims hit hard.

If your tire pressure is too high, you may notice a loss of grip on loose terrain where the tires spin more than they should.  

Another way to determine the correct tire pressure is the “rim clean.”  Right on the edge of the shiny aluminum tire rim where it meets the tire, you’ll see a slight shinier ring around the edge.  The shiny area is from the tire rubbing on the rim.  This is the rim clean.  Most people recommend that this shiny area should be 3-4mm to determine a perfect tire pressure.  If the rim clean is too large, increase the tire pressure.  Too small?  Decrease it.

Another thing to look for is the PSI change as altitude and heat change.  Check your tire pressure at the start of your ride, then go out and ride for 30 minutes and immediately check your tire pressure again when you stop.  You may see a difference of an increased 3-4 psi from the heat of the tire.  If this is the case, you may want to lower your tire pressure at the start of your ride.

Also, because of different power transfers in four strokes vs two strokes, you may want to slightly increase tire pressure in the front tire on a four stroke.

When to Replace Your Tires

A good way to know if it’s time to look at replacing your tires is when the little knobbies on the sides start to split or break away.  At this point, your tire will start to have less traction in the corners and the tire as a whole is not as thick so you’ll be more likely to experience flats.

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